Ganja buffs in a van covered with images of pot leaves and the words “Medical Marijuana Doctors” were busted with a massive stash of cocaine and ecstasy after cops searched their mellow green machine.

Jessica Cahill, Jonathon Schwartz, John Nicalozza and Jason Tracin — all of Nassau County and employees of a medical-marijuana Web site — were on the Long Island Expressway near Great Neck at about 3 p.m. Friday, en route to an Atlantic City seminar on how to grow pot, when cops pulled them over, sources said.

They were allegedly carry­ing bags of cocaine and the club drug molly, police sources said.

Cops said they stopped the “commercial” van for rolling along in the non-commercial HOV lane.

But lawyer Mark Heller said the van was registered as a private vehicle — so police had no right to pull it over or search the occupants.

“[Cops] took a short cut and searched the vehicle without probable cause,” Heller said.